Electrical current is typically supplied to end users through high voltage transmission lines that typically are located on elevated structures above the surface of the earth. It is frequently necessary to de-energize a portion of the current transmission lines in order to allow workmen to conduct service operations under safe working conditions. To facilitate de-energization of only a portion of the electric transmission circuitry, there will be provided switching mechanisms that may be manipulated in such manner as to make and break the electrical connection between sections of each of the transmission conductors involved. For example, a branch conductor may be connected to a main line conductor through a simple switch mechanism, the main line and branch line being separated by an insulator with a switching mechanism that bridges the insulator when the switch mechanism is in the closed position thereof. Typically such switches are located on structure that is supported by elevated towers or poles the switches being manipulated by means of long insulated switch actuating rods that may be manipulated by workmen at ground level or located at a considerable distance from the switch devices being manipulated. By using one of these long rods, a workman can insert an actuating hook of the rod into an eye on the switch device and, by applying a downward force, and easily move the switch to its open position. Conversely, the workman can push the switch upwardly by means of the rod and can easily move the switch to its closed position to energize the branch conductor from the main line conductor. Typically the switch devices are of pivotal nature and are supported by pivot structure located at the lower extremity of the insulator structure. The switch mechanism includes an elongated movable element having a current conducting capability that is pivotally connected at one extremity thereof to the support structure and may be pivoted between open and closed positions relative to a switch plate that receives the free extremity of the elongated movable switch element in the closed position thereof. The switch plate is electrically connected with the main line conductor through suitable bracket structure. As mentioned above, each of the switches is opened by pulling downwardly on a switch actuating eye by means of an elongated insulated rod. Typically, the pivotal portion of the switch mechanism is allowed to pivot downwardly to a near vertical condition and to merely hang suspended from its support structure. In this condition, workmen can service electrical equipment connected to the de-energized branch conductor under safe operating conditions.
At times, an insulator can become conductive under certain conditions. For example, if lightning should strike the electrical equipment that provides support for the electrical transmission conductors, the insulator can be rendered conductive by the enormous amount of electrical potential that is placed across it by the electrical discharge of the lightning. This is a very infrequent occurance, but, when it does occur, a condition of electrical potential can be developed across the insulator, allowing the branch conductor to be energized even though the switch mechanism may be in the open position thereof. When insulators remain in service for extended periods of time, depending upon the operating circumstances involved, it is possible for an insulator to break down to the point that it becomes conductive. This also is a very infrequent occurance, but when it does occur, a very dangerous condition exists. It is therefore a primary object of the present invention to provide means for insuring grounding of branch conductors under conditions where a switching mechanism is in the open position thereof, thereby providing workmen servicing the branch conductors or any equipment connected thereto with safe working conditions.
It is also an important feature of the present invention to provide a novel switching mechanism for electrical conductors that includes means for maintaining a de-energized supply conductor under a condition of ground potential for extended periods of time to insure that any sudden application of electrical energy to a de-energized branch conductor is immediately transmitted to ground potential and does not present a hazardous condition for workmen that might be involved in servicing the branch conductor or its connected equipment.
Among the several objects and features of the present invention is noted the contemplation of a novel switching mechanism for electrical supply conductors that includes means for detecting the flow of high voltage current across an insulator to ground in order that a defective insulator may be located and replaced so as to eliminate a potentially hazardous condition.
It is also a feature of the present invention to provide a novel grounding mechanism for electrical switches that is of inexpensive nature, is reliable in use and low in cost.
Other and further objects, advantages, and features of the present invention will become apparent to one skilled in the art upon full consideration of the present disclosure. The form of the invention, which will now be described in detail, illustrates the general principals of the invention, but it is to be understood that this detailed description is not to be taken as limiting the scope of the present invention.